Formation of metal shapes



April 6, 1943 c. D. coxE 2,316,144

FORMATION OF METAL SHAPES Filed Allg. 30, 1941 H. '4 -ss l faq! AGENTPatented Apr. 6, 1943 FORMATION OF METAL SIIAIES Charles D. Coxe,Bridgeport, Conn., assgnor to Remington Arms Company, Inc., a.corporation of Delaware Application August 30, 1941, Serial No. 408,926

43 Claims.

This invention relates to the method and apparatus for making metallicshapes directly from molten metal by floating the metal on a fluid, andis particularly adapted for the production of metallic sheets. A methodand equipment of this character are disclosed in applicants priorapplication, Serial No. 334,537, filed May 1l, 1940, patented October13. 1942, Patent No. 2,298,348.

The present invention comprises certain immovements and refinements uponthe disclosure of the earlier application, such improvements including amore accurate control of the rate of heat exchange between the body orsheet of metal beingformed and contiguous media, accompanled bymetallurgical improvement in the body or sheet.

It is an object of this invention to provide. elements for improving thesurface characteristics of metal sheets being formed upon a fluid bath.More particularly, an object of thisinventionl is to provide improvedmeans to control the rate of heat removal yfrom the surfaces of themetal sheets being formed so as to obviate the forma tion of undesirablevestigial shrinkage effects. Another object is to correlate rates ofheat dissipation from different surfaces of the sheet being formed insuch a way as to effect substantially simultaneous solidificationthereof, and to insure that no exterior portion solidifies later thanthe adjacent interior portion. A further object is to provide animproved apparatus for cleaning the bath meta-l off of the surface ofthe finished sheet. A still further object is to provide an improvedfeeding device for uniformly flowing the molten metal to be shaped ontothe surface of the molten metal bath.

Other objects. features and advantages of the invention will appear fromthe following detailed description and drawing, which give severalillustrative forms of the invention.

In the drawing:

Fig, 1 is a diagrammatic side elevation of one type of apparatus used inconjunction with the devices of this invention, with a portion cut awayshowing the heated squeeze rolls. i

Fig. 2 is a detailed side elevation partially in section of theapparatus of Fig. l, not including the squeeze rolls.

Fig. 3 is a plan view of Fig. 2.

Fig. 4 is an end elevation on line 4 4 of Fig. 2, showing details of theendless chain.

Fig. 5 is an enlarged fragmentary section of the apparatus of Fig. 2adjacent the heat control surfaces, showing the automatic regulatingdevices.

Fig. 6 is a fragmentary side elevation of the apparatus of Fig. 2showing modified means for regulating the temperature of the bath.

As disclosed in applicants prior application, mentioned above, theformation of metal articles directly from molten metal by flowing themolten metal to be shaped onto the surface of a fluid bath necessitatesthat the bath material be one having a lower melting point and a higherboiling point than the freezing point of the met-al which is to beshaped, and the specific gravity of the bath be either greater or lessthan the specific gravity of the metal to be shaped, depending upon themode in which the invention is carried out.

In illustrating the improvements of this invention, applicant hasarbitararily chosen a bath having a relatively high specific gravity sothat it will stay at the bottom of the container while the molten metalwhich is to be shaped will iloat on top of the bath. It will beunderstood, however, that applicants invention is also applicable whenthe specific gravities of bath and metal being cast are reversed.

As an example, lead having a melting point of 620 F., a boiling pointhigher than 2800 F., and a specific gravity of 11.34 may be used as themolten bath; and aluminum having a melting point of about 1220 F. and aspecific gravity of 2.7 may be the metal to be shaped.

If the aluminum be maintained at a temperature of about 1274 F., andmost of the lead kept at a temperature of about 752 F., aluminum willfreeze at the interface of the two metals. `The resultant layer ofaluminum can be removed,

making room at the interface for another portion of the aluminum tofreeze; and the frozen aluminum may be removed continuously in the formof -an endless strip or a strip of the length desired.

Although lead and aluminum have been cited as suitable metals formolding relatively thin sheets of aluminum directly on the fluid lead,it will be understood that other combinations of metals and non-metalsmay be used, the requisites being merely that the two be immiscible inthe liquid state and show properly related freezing points, boilingpoints, and specific gravities.

Referring to Fig. 1, the metal to be shaped is poured into an improvedpouring box lll, which feeds the metal on to the surface Il of the fluidbath held in the carrier I2. Although the pouring box il! is shownlocated with the pouring lip rearwardly of a point adjacent the entranceto the conveyor chains 21, it will be understood that, if warranted byimproved operation, the

pouring box may be located forwardly so that the pouring lip 25 ispositioned adjacent the entrance to the conveyor chains. Further,although the pouring box is shown in plan view as being substantiallyrectangular, it will be understood that the box may be circular or haveother geometrical shapes.

A circulating pump I3 and cooler Il illustrate one example of means tomaintain the temperature of the greater portion of the fluid bathuniform. 'Ihe pump I5 and cooler I6 are adapted, as hereinafterdescribed, to circulate a` cooled fluid through suitable heat absorbingmeans, arranged to cool the upper surface of the metal being cast.

The pair f rolls I1, I1 shown in the cut away portion of Fig. 1 aresuitablydesigned as improved means for removing any bath metal which maybe clinging to the surface of the cast metal sheet as it is withdrawnfrom the apparatus by the pinch rolls I 8, I8. The rolls I'I, I'I aresuitably arranged as squeeze rolls, and are heated, as for instance byburners I9, I8 so that as the metal sheet passes through the heatedsqueeze rolls the fluid metal of the bath clinging thereto is cleaned orstripped from the metal strip while the bath metalV is in a uid state.The action of the rollers is therefore substantially that of a wringerfor wringing on the fluid bath. Although the burners I9, I9, asillustrated, are directed on to the outer surface of the squeeze rolls,it will be understood that other arrangements for heating the rolls maybe made, as, for example, locating the burners on the inside of therolls.

An alternative means for removing the uid bath material comparable tothat of the heated squeeze rolls is the use of a blast of hot gas whichmay be directed on to the surface of the frozen sheet from a blowersimilar to that shown at 38 in Fig. 2, but located in substantially theposition of the squeeze rolls.

The metering or pouring box III illustrates suitable means adapted touniformly feed the metal to be shaped on to the surface of the fluidbath. To this end, the pouring box I is divided into upper and lowersections and 2I respectively by an apertured partition 22. Bymaintaining a substantially constant level of molten metal in the uppersection 20, the aperture 23 of the partition 22 feeds the molten metalat a substantially uniform rate into the lower section 2| of the pouringbox and from thence the metal flows under a skimming dam 24 to a pouringlip 25. The dam 2| is one example of suitable means for smoothing outsuch turbulence or ripples in the molten metal as may be caused by theflow of the metal from the upper section of the box into the lowersection and for holding back the dross. The lip 25 is shown immersed inthe metal of the bath and is effective for directing a uniformly smoothflow of molten metal on to the surface of the bath.

As the molten metal ows over the pouring lip 25 and contacts the surfaceII of the fluid bath. freezing tends to occur sooner at the interface orpoints of impingement of the metals than at that portion of the castmetal away from the interface, i. e. the upper surface, depending upohthe thickness of the cast metal and the relative differences oftemperature between the bath and other media in contact with thesurfaces of the metal.

It is desirable, therefore, to provide means for controlling thedissipation of heat from the respective surfaces of the cast metal sothat the freezing, and in particular the initial freezing, at theinterface is retarded and maintained at a rate which permits freezing ofthe upper surface prior to complete freezing upwardly through the castmetal from the interface. It is also desirable that the freezingcontinue uniformly from the advanced portion of the cast sheetrearwardly to the pouring lip so as to preclude the formation ofintermediate frozen portions or frozen islands in the sheet which wouldgive rise to shrinkage defects in the surface of the sheet. In theserespects it may be emphasized that the regulation of the dissipation ofheat from the surfaces of the cast metal need not necessarily becontinued throughout thev entire time required for completesolidiflcation of the strip for it has been found that once the outersurfaces of the metal have frozen, the subsequent solidiilcationinwardly may proceed at its own pace without the occurrence of shrinkagecavities or other defects on the outer surfaces. Hence, as hereinafterdescribed, the heat dissipation controlling means are locatedsubstantially adjacent the initial point of impingement of the castmetal on the fluid bath, but it will be clear that these means mayextend over a substantial length of the bath if desirable.

One example of the means employed to retard the cooling 0f the edges ofthe cast sheet and simultaneously to displace the metal sheet as it isformed comprises the endless chains 21 shown in Figs. 2 and 4, which aresuitably driven through gears 28 and shafts 29 from some suitable sourceof power (not shown). The chain comprises a plurality of independentlymounted substantially vertical metal plates 30 (see Fig. 4), which areadvanced in the direction shown by the arrow in Fig. 3, each plate beingfaced with a suitable plate or block 3| composed of a substance havinglow heat conductivity and comprising engaging means for engaging andlimiting the margins of the cast metal. The latter ows from the lip 25of the pouring box into engagement With the heat insulating blocks 3I ofthe endless chainwhich displace the strip of metal over the surface ofthe bath, the metal gradually solidifying substantially throughout itsthickness. The use of the facing blocks of low heat conductivity greatlyretards the dissipation of heat from the edges of the cast metal sheetand contributes toward a more uniformly controlled cooling of thesurfaces of the metal sheet.

Because the sheet being formed is of necessity at a higher temperaturethan the temperature of the bath, it is evident that the molten bathwill absorb heat from the cast metal and therefore the bath must becooled or so designed that the proper temperature differential will bemaintained. This may be done in any one of several ways, as, forexample, the fluid bath material may be drawn into the pipe 33 (see Fig.2) and passed through a suitable cooler I4. A pump I3 may be employed toreturn the bath fluid toward the container I2 at a temperature such thatthe metal sheet will .properly freeze on the surface of the bath.

One means of controlling the initial freezing or rate of heat exchangeat the interface of the lower surface of the cast metal and the fluidbath is to provide a baille plate 35 immersed in the bath and adjacentthe pouring lip 25 of the pouring box. Insofar as the baffle restrictsthe circulation of the bath metal in this localized area, the

cooling caused by circulation is counteracted and hence that restrictedarea of the bath metal adjacent the point of impingement of the metaland the bath is maintained at a substantially higher tem-perature thanthe temperature of the remaining portion of the bath. The length of thebaffle relative to the length of the metal is substantially in theproportions shown and is such as to provide a localized area ofrelatively high temperature sufficient to retard the initial freezing ofthe lower surface of the cast metal as it is fed on to the fluid bath sothat the dissipation of heat from the lower surface and upper surfacemay be held at substantially the same rate. Although the baffle showncomprises a steel plate, it will be clear that the -baflie may takeother forms and may be made of other suitable materials. It may beobserved too that, in addition to its function as means for localizingthe heat of the bath, the baille also dampens and smooths out thesurface ripples of the bath.

Suitable means are also provided for controlling the dissipation of heatfrom the upper s urface of the cast metal. Referring to Fig. 2, 36 is `asuitable heat absorber comprising a hollow block adapted to becontinuously cooled by water which may be circulated through the blockand a cool mist over the surface of the cast metal sheet. With thisconstruction, the cooling effect of the water jacketed surface 31 andthe cool draft of gas or mist may supplement each other or may be usedindependently of each other.

Suitable means for automatically regulating the cooling effect of theheat absorber and cool- -ing draft and the heating effect of the bafthecooler I6 by a pump i5 and suitable pipe connections. The block 36 maybe supported between the endless chains 21 as .shown in Fig. 3 in thelocalized areaof the baffle 35 with its lower surface 21 immediatelyabove the surface of the bath. As the cast metal flows on to the bathfrom the pouring lip 25 and is moved forwardly by the endless engagingmeans 3i, the upper surface of the cast metal Ipasses immediatelybeneath the relatively cool surface 31 whereby the removal ordissipation of heat from the upper surface of the cast metal isaccelerated. By regulating the cooling eect of the heat absorber 36, theinitial rate of cooling of the upper surface of the cast metal may thusbe accelerated to approach the initial rate of cooling of the lowersurface.

The heat absorber or water jacket 36, shown in Fig. 2, is a hollowblock, but it will be clear that the absorber may comprise spacedlengths of tubing or have other conventional radiator constructions, andthat any suitable fluid may be circulated instead of water.

It is also possible to control the dissipation of heat from the uppersurface of the cast metal by sweeping the upper surface with a flow ofrelatively cool air or gas. To this end a blower 38 having suitabledrive means 3l, diagrammatically illustrated in Fig. 2, is suitablysupported in a casing 40, which comprises a substantially hermeticallysealed hood arranged to maintain an atmosphere of air or other suitablegas in contact with the surface of the metal bath and cast metal sheet.Suitable cooling means 4| may be used to cool the recirculated gas and aduct 42 is provided for directing the recirculated gas over the uppersurface of the cast sheet. The location of the duct 42 is consistentwith the use of av heat absorber of the type shown, but it will bc clearthat byusing a radiator type absorber, a vertical down draft of air maybe directed through the tubes of the radiator on to the upper surface ofthe cast sheet. An additional cooling means augmenting the coolingeffect of the draft of cool air or gas may be the use of a suitablespray nozzle 420 located in the mouth of the duct 42 and supplied with acooled fluid, such as water, which is adapted to be atomized by thedraft of air to form 76 fle relative to the respective upper and lowersurfaces of the cast metal, whereby the initial dissipation of heat fromthese surfaces may be maintained substantially equivalent, may compriseany well-known type of heat responsive device such as the pyrometersshown at 45 and 46 (see Fig.'5) suitably located adjacent the up- .perand lower surfaces respectively of the cast metal sheet. The pyrometersmay be connected in any conventional manner to a suitable powercontrolling device for automatically regulating the speed of operationof the pumps of the respective circulated cooling media.

In Fig. 6 is shown an alternative form of metal bath cooling means whichmay be used instead of that shown in Fig. 2. This modification comprisesa temperature control system embodying the use of a suitable heatresponsive device such as a thermo-couple 41 suitably immersed in afluid bath adjacent the pouring lip 35. The

as a pyrometer control at 48, a power control 49, and a motor 50,diagrammatically shown in Fig. 6, which automatically regulate the speedof operation of the bath circulating pump 5|. The latter is shownprovided with a duct 52 immersed in the bath for delivering the cooledfluid metal adjacent the upper surface of the bath. Thus, as thetemperature of the bath adjacent the thermo-couple drops, due to toorapid circulation, the thermo-couple automatically reduces the speed ofoperation of the pump, which in turn reduces the rate of circulation orcooling of the bath. Similarly, if the temperature of the bath tends torise too high for ideal operating conditions, the thermo-coupleautomatically reduces the cooling of the bath. 'In this modiedapparatus, the thermo-couple 41 may also act in conjunction with thepyrometer 45 of Fig. 5, to automatically maintain substantiallyequivalent rates of cooling .of the upper and lower surfaces of themetal bath.

By the invention disclosed herein, metal sheets cast upon a fluid bathmay be produced having substantially smooth surfaces and edges free fromshrinkage cavities or dendritic-like structure, thus greatly enhancingthe value of the product. As this is the first time that a satisfactorymethod and apparatus have been developed for such purpose, the inventionis not limited to the details disclosed but is to be construed asbroadly covering all equivalent devices and processes falling within thescope of the appended claims.

What is claimed is:

1. Apparatus for the casting of metal by floating said metal upon afluid immscible with said metal comprising a substantially stationaryfluid bath container to form a planar surface fluid bath, a fluid insaid container, means for regulating the exchange of heat between saidmetal and the media in contact therewith, said means comprising devicesfor sustaining the heat at a localized area of said fluid, and means forcooling the atmosphere above and adjacent said metal.

2. Apparatus for the casting of metal by floating said metal upon afluid immiscible with said metal comprising a substantially stationaryfluid bath container to form a planar surface fluid bath, a fluid insaid container, means for regulating the @Xchange of heat between saidmetal and the media in contact therewith, said means comprlsing'a heatexchange retarding device for sustaining the heat at a localized area ofsaid fluid. and heat exchange accelerating means for cooling thevatmosphere above and adjacent said metal.

3. Apparatus for the casting of metal by floating the metal upon a fluidsubstantially immiscible with said metal comprising means immersed insaid fluid adapted to retard the rate of heat exchange between saidmetal and said fluid.

4. Apparatus for the casting of metal by floating the metal upon a fluidsubstantially immiscible with said metal comprising means immersed insaid fluid adapted to control the rate of heat exchange between saidmetal and said fluid.

5. Apparatus for the casting of metal by floating the metal upon a fluidimmiscible with said metal comprising means immersed in said fluidadapted to provide a localized area of higher temperature than otherportions of the fluid, thereby retarding the rate of heat exchangebetween said metal and said fluid.

6. Apparatus for the casting of metal by floating the metal upon a fluidimmiscible with said metal comprising means immersed in said fluidadapted to obstruct the circulation of said fluid, thereby retarding therate of beat exchange between said metal and said fluid.

7. Apparatus for the casting of metal by floating the metal upon a fluidsubstantially immiscible with said metal comprising means immersed insaid fluid adapted to retard the rate of heat exchange between saidmetal and said fluid. and means to accelerate the dissipation of heatfrom the upper surface of said metal. Y

8. Apparatus for the casting of metal by floating the metal upon a fluidsubstantially immiscible with said metal comprising means immersed insaid fluid adapted to control the rate of heat exchange between saidmetal and said fluid, and means to control the dissipation of heat fromthe upper surface of said metal.

9. Apparatus for the casting of metal by iioating said metal upon afluid substantially immiscible with said metal, comprising a cooledsurface supported above said metal for cooling the atmosphere, therebyaccelerating the dissipation of heat from the upper surface of saidmetal.

10. Apparatus for the casting of metal by floating said metal upon a uidsubstantially immiscible with said metal, comprising the combination ofa cooled surface supported above said metal, and blower means for movingair across said cooled surface, thereby accelerating the dissipation ofheat from the upper surface of said metal.

1l. Apparatus for the casting of metal for floating said metal upon ailuid substantially immiscible with said metal, comprising meansimmersed in said fluid adapted to provide a localized area of highertemperature than other portions of the fluid, thereby retarding the rateof heat exchange between said metal and said fluid; and means supportedabove said metal for cooling the atmosphere, thereby accelerating thedissipation of heat from the upper surface of said metal.

12. Apparatus for the casting of metal by floating said metal upon a.fluid immiscible with said metal including means'for displacing themetal,

comprising elements of low heat conductivity contacting the margins ofsaid metal.

13. Apparatus for the casting oiv metal by floatlng said metal uponafluid immiscible with said metal including means for moving the metalover the .surface of said fluid, comprising elements of low heatconductivity contacting the edges of said metal and simultaneouslylimiting the width thereof. v

14. Apparatus for the casting of metal by floating said metal upon ametal bath immiscible with the metal to be cast. comprising means fordisplacing the cast metal and means to remove the bath metal from thedisplaced metal while said bath metal is in a fluid condition.

15. Apparatus for the casting of metal by floating said metal upon ametal bath immiscible with the metal to be cast, comprising means formoving the cast metal over the surface of said bath, and squeezing meansto remove the bath metal from the moving cast metal while said bathmetal is in a fluid condition.

16. Apparatus for the casting of metal by floating said metal upon ametal bath immiscible with the metal to be cast, comprising means formoving the cast metal over the surface of said bath, and heated means toremove the bath metal from the moving cast metal while said bath metalis in a fluid condition.

17. Apparatus for the casting of metal by iioating said metal upon ametal bath immiscible with the metal to be cast. comprising means formoving the cast metal over the surface of said bath, and heated squeezerolls to remove the bath metal from the moving cast metal while saidbath metal is in a fluid condition.

18. Apparatus for the casting of metal by oating said metal upon a fluidsubstantially immiscible with said metal, comprising means adapted tofeed the metal on to the surface of said fluid, said means comprising apouring box having a pouring lip immersed in said uid to uniformly feedthe metal on to the surface of the fluid.

19. In an apparatus for casting metal sheets directly from molten metal,the combination comprising: a substantially stationary molten metal bathcontainer to form a planar surface molten metal bath, a molten metal insaid container, the metal of the bath being substantially immisciblewith and having a lower melting point than the molten metal; means tofeed the molten metal into contact with the metal bath so that thefreezing will occur at the interface of the two metals; and means toretard the rate of heat exchange between the lower surface of the moltenmetal and the upper surface of the bath.

20. In an apparatus for casting metal sheets directly from molten metal,the combination comprising: a metal bath, the metal of the bath beingsubstantially immiscible with and having a lower melting point than themolten metal; a pouring box to uniformly feed the molten metal intocontact with the metal bath so that the freezing will occur at theinterface of the two metals; means immersed in said metal bath adjacentsaid box to retard the rate of heat exchange between the lower surfaceof the molten metal and the metal bath; and means to displace the atleast partially frozen sheet of molten metal.

21. In an apparatus for casting metal sheets directly from molten metal,the combination comprising: a stationary metal bath, the metal of thebath being substantially immiscible with and having a lower meltingpoint than the molten metal; a pouring box having a lip to feed themolten metal into contact with the molten metal bath so that thefreezing will occur uniformly at the interface of the two metals; meansto circulate the metal of said bath: a baille immersed in said metalbath adjacent said lip and relatively close to the underside of themolten metal to restrict the circulation of the' bath metal and therebyto retard the rate of heat exchange between the lower surface of themolten metal and the metal bath; means to displace the at leastpartially frozen sheet of molten metal; and means to remove fluid bathmetal from said sheet.

22. In an apparatus for casting metal sheets directly from molten metal,the combination comprising: a metal bath, the molten metal of the bathbeing substantially immiscible with and having a lower melting pointthan the molten metal; a pouring box having a lip to feed the moltenmetal into contact with the metal bath so that the freezing will occuruniformly at the interface of the two metals; means to circulate Y themetal of said bath; heat responsive meansv immersed in said metal bathadjacent said pouring lip; means responsive to said heat responsivemeans to control the operation of said circulating means and thereby toretard the rate of heat exchange between the lower surface of the moltenmetal and the metal bath; means to displace the at least partiallyfrozen sheet of molten metal; and heated `means to squeeze fluid bathmetal from said sheet.

23. In an apparatus for casting metal sheets directly from molten metal,the combination comprising: a metal bath,4 the metal of the bath beingsubstantially immiscible with and having a lower melting point than themolten metal; means immersed in said bath to feed the molten metal intocontact with the metal bath so that the freezing will occur at theinterface of the two metals; and means to control the dissipation ofheat from the upper surface of the molten metal.

24. In an apparatus for casting metal sheets directly from molten metal,the combination comprising: a metal bath, the metal of the bath beingsubstantially immiscible with and having a lower melting point than themolten metal; means immersed in saidl bath to feed the molten metal intocontact with the metal bath so that the freezingwill occur at theinterface of the two metals; cooling means to accelerate the dissipationof heat from the upper surface of the molten metal; and means todisplace the at least partially frozen sheet of molten metal.

25. In an apparatus for casting metal sheets directly from molten metal,the combination comprising: a metal bath, theI metal of the bath beingsubstantially immiscible with and having a lower melting point than themolten metal; means to feed the molten metal into contact with the metalbath so that the freezing will occur at the interface of the two metals;cooling means comprising a'iuid cooled surface supported above the uppersurface of the molten metal to accelerate the dissipation of heat fromthe upper surface of said metal; and means to displace the at leastpartially frozen sheet of molten metal.

26. In an apparatus for casting metal sheets directly from molten metal,the combination comprising: a metal bath, the metal of the bath beingsubstantially immiscible with and having a lower melting point than themolten metal; means to feed the molten metal into contact with the metalbath so that the freezing will occur at the interface of the two metals;means to maintain a cooled atmosphere over the upper surface of themolten metal to accelerate the dissipation of heat from the uppersurface of said metal; means to displace the at least partially frozensheet of molten metal; and means to remove iluid bath metal from saidsheet.

27. In an apparatus for casting metal sheets directly from molten metal,the combination comprising: a metal bath, the metal of the bath beingsubstantially immiscible with and having a lower melting point than-themolten metal; a pouring box having a lip immersed in said bath to feedthe molten metal into contact with the metal bath 'so that the freezingwill occur uniformly at the interface of the two metals; means tomaintain a cooling gas over the upper surface of the molten metal; ablower for moving the gas over said surface; gas cooling meanscomprising a fluid cooled surface supported above the upper surface ofthe molten metal to accelerate the cooling of the upper surface of saidmetal; means to displace the at least partially frozen sheet; and heatedmeans to squeeze fluid bath metal from said sheet.

28. In an apparatus for casting metal sheets directly from molten metal,the combination comprising: a metal bath, the metal of the bath beingsubstantially immiscible with and having a lower melting point than themolten metal; means to feed the molten metal into contact with the metalbath so that the freezing will occur at the interface of the two metals;and means for displacing the partially frozen molten metal comprisingelements of low heat conductivity contacting the margins of said moltenmetal.

29. In an apparatus for casting metal sheets directly from molten metal,the combination comprising: a metal bath, the metal of the bath beingsubstantially immiscible with and having a lower melting point than themolten metal; means to feed the molten metal into contact with the metalbath so that the freezing will occur at the interface of the two metals;means for moving the partially frozen molten metal over the surface ofsaid bath comprising elements of low heat conductivity contacting theedges of the partially frozen metal to retard the dissipation of heatfrom the edges of said metal: and means to remove fluid bath metal fromthe at least partially frozen sheet.

30. In an apparatus for casting metal sheets directly from molten metal,the combination comprising: a metal bath, the molten metal of the bathbeing substantially immiscible with and having a lower melting pointthan the molten metal; a pouring box having a pouring lip immersed insaid bath to feed the molten metal into contact with the metal bath sothat the freezing will occur at the'interface of the two metals; meansincluding two endless chains having engaging means for moving thepartially frozen sheet of molten metal along the surface of the metalbath, said engaging means comprismiscible with and having a lowermelting point than the molten metal; means to feed the molten metal intocontact with the metal bath so that the freezing will occur at theinterface of the two metals; means to control the rate of heat exchangebetween the lower surface of the molten metal and the metal bath; meansto control the dissipation of heat from the upper surface of the moltenmetal being shaped; and means to displace the at least partially frozensheet.

32. In an apparatus for casting metal sheets directly from molten metal,the combination comprising: a metal bath, the metal of the bath beingsubstantially immiscible with and having a lower melting point than themolten metal; a pouring box having a pouringlip immersed in said bath touniformly feed vthe molten metal into contact with the metal bath sothat the freezing will occur at the interface of the two metals; abaille immersed in said metal bath vadjacent said lip to retard the rateof heat exchange between the lower surface of the molten metal and themetal bath; cooling means comprising a fluid cooled surface supportedabove the upper surface of the molten metal to cool the atmosphere incontact therewith, thereby accelerating the dissipation of heat fromsaid surface; means to displace the partially frozen metal sheetcomprising elements of low heat conductivity engaging the edges of thesheet; and means comprising heated rolls to squeeze fluid vbath metalfrom the partially frozen sheet.

33. In the manufacture of metal articles directly from molten metal, theprocess comprising the steps of providing a bath of metal substantiallyimmiscible with the molten metal to be formed, feeding the molten metalinto contact with the metal bath, and maintaining the rates of heatexchange which exist between the surfaces of the molten metal and themedia in contact therewith substantially equal.

34. In the manufacture of metal articles directly from molten metal, theprocess comprising the steps of providing a bath of metal substantiallyimmiscible vwith the molten metal 'to be formed, feeding the moltenmetal uniformly into contact with the metal bath, retarding the coolingof the lower surface of the molten metal by sustaining the heat at alocalized area of said metal bath so that said lower surface cools offat substantially the same rate as the upper surface of said moltenmetal, and then continuously displacing the partially frozen moltenmetal from the bath.

35. In the manufacture of metal articles directly from molten metal, theprocess comprising the steps of providing a bath of metal substantiallyimmiscible with the molten metal to be formed, feeding the molten metaluniformly into contact with lthe metal bath, accelerating the cooling ofthe upper surface of the molten metal so that said upper surface coolsoff at substantially the same rate as the lower surface, and thencontinuously displacing the partially frozen molten metal froml thebath.

36. In the manufacture of metal articles directly from molten metal,theprocess comprising the steps of providing a bath of metalsubstantially immiscible with the molten metal to be formed, uniformlyfeeding the molten metal into contact with the metal bath, circulatingthe bath metal, retarding the circulation of the metal bath locally sothat 'the lower surface of the molten metal cools oi at substantiallythe same rate as the upper surface of said molten metal,

and then continuously removing the partially frozen molten metal fromcontact with the bath.

37. In the manufacture of metal articles directly from molten metal, theprocess comprising the steps of providing a bath of metal substantiallyimmiscible with the moltenv metal to be formed, uniformly feeding themolten metal into contact with the metal bath, maintaining a draft ofrelatively cool gas over the upper surface of the molten metal so thatthe upper surface of said metal cools off at substantially the same rateas the lower surface of said metal, and then continuously removing thepartially frozen metal from contact with the bath.

38. In the manufacture of metal sheets directly from molten metal, theprocess comprising the steps of providing a bath of metal substantiallyimmiscible with and having a lower melting point than the metal to beformed into sheets, uniformly feeding the molten metal into contact withthe metal bath, accelerating the cooling of the upper surface of thepartially frozen molten metal by flowing a relatively cool fluid oversaid surface, circulating the bath metal, retarding the cooling of thelower surface of said partially frozen sheet by locally restricting thecirculation of the metal bath whereby the respective upper and lowersurfaces cool olf at substantially the same rate, and then continuouslysqueezing fluid bath metal from the partially frozen metal.

39. Apparatus for the casting of metal by floating said metal upon afluid immiscible with said metal, comprising means for maintainingsubstantially uniform rates of heat exchange between the surfaces ofsaid metal and the media in contact therewith.

40. Apparatus for the casting of metal by floating said metal upon afluid immiscible with said metal, comprising means adjacent the surfacesof said metal for maintaining the rates of heat dissipation from thesurfaces of said metal substantially equivalent.

41. Apparatus for the casting lof metal by floating said metal upon afluid immiscible with said metal, comprising heat responsive devicesadjacent the upper and lower surfaces of said metal, and meansresponsive to said devices for automatically maintaining the rates ofheat dissipation from said surfaces substantially equivalent.

42. In an apparatus for casting metal sheets directly from molten metal,the combination comprising: a metal bath, the metal of the bath beingsubstantially immiscible with and having a lower melting point than themolten metal; means to direct. the two metals into contact with eachother; and means for maintaining substantially uniform rates of heatexchange between the surfaces of said molten metal and the media incontact therewith.

43. In an apparatus for casting metal sheets directly Vfrom moltenmetal, the combination comprising: a metal bath, the metal of the bathbeing substantially immiscible with and having a lower melting pointthan the molten metal; means to direct the two metals into contact witheach other; heat responsive devices adjacent the upper and lowersurfaces of said molten metal; and means responsive to said heatresponsive devices for automatically maintaining the rates of heatdissipation from said surfaces substantially equivalent.

CHARLES D. COXE.

